/**
 * Copyright (c) E.Y. Baskoro, Research In Motion Limited.
 * 
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without 
 * restriction, including without limitation the rights to use, 
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the 
 * Software is furnished to do so, subject to the following 
 * conditions:
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 
 * OTHER DEALINGS IN THE SOFTWARE.
 * 
 * This License shall be included in all copies or substantial 
 * portions of the Software.
 * 
 * The name(s) of the above copyright holders shall not be used 
 * in advertising or otherwise to promote the sale, use or other 
 * dealings in this Software without prior written authorization.
 * 
 */
package com.walkline.util.json;

import java.io.IOException;
import java.io.Writer;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

/**
 * A JSONObject is an unordered collection of name/value pairs. Its external form is a string wrapped in curly braces with colons between the names and values, and commas between the values and names. The internal form is an object having <code>get</code> and <code>opt</code> methods for accessing the values by name, and <code>put</code> methods for adding or replacing values by name. The values can be any of these types: <code>Boolean</code>, <code>JSONArray</code>, <code>JSONObject</code>, <code>Number</code>, <code>String</code>, or the <code>JSONObject.NULL</code> object. A JSONObject constructor can be used to convert an external form JSON text into an internal form whose values can be retrieved with the <code>get</code> and <code>opt</code> methods, or to convert values into a JSON text using the <code>put</code> and <code>toString</code> methods. A <code>get</code> method returns a value if one can be found, and throws an exception if one cannot be found. An <code>opt</code> method returns a default value instead of throwing an exception, and so is useful for obtaining optional values.
 * <p>
 * The generic <code>get()</code> and <code>opt()</code> methods return an object, which you can cast or query for type. There are also typed <code>get</code> and <code>opt</code> methods that do type checking and type coersion for you.
 * <p>
 * The <code>put</code> methods adds values to an object. For example,
 * 
 * <pre>
 * myString = new JSONObject().put(&quot;JSON&quot;, &quot;Hello, World!&quot;).toString();
 * </pre>
 * 
 * produces the string <code>{"JSON": "Hello, World"}</code>.
 * <p>
 * The texts produced by the <code>toString</code> methods strictly conform to the JSON sysntax rules. The constructors are more forgiving in the texts they will accept:
 * <ul>
 * <li>An extra <code>,</code>&nbsp;<small>(comma)</small> may appear just before the closing brace.</li>
 * <li>Strings may be quoted with <code>'</code>&nbsp;<small>(single quote)</small>.</li>
 * <li>Strings do not need to be quoted at all if they do not begin with a quote or single quote, and if they do not contain leading or trailing spaces, and if they do not contain any of these characters: <code>{ } [ ] / \ : , = ; #</code> and if they do not look like numbers and if they are not the reserved words <code>true</code>, <code>false</code>, or <code>null</code>.</li>
 * <li>Keys can be followed by <code>=</code> or <code>=></code> as well as by <code>:</code>.</li>
 * <li>Values can be followed by <code>;</code> <small>(semicolon)</small> as well as by <code>,</code> <small>(comma)</small>.</li>
 * <li>Numbers may have the <code>0-</code> <small>(octal)</small> or <code>0x-</code> <small>(hex)</small> prefix.</li>
 * <li>Comments written in the slashshlash, slashstar, and hash conventions will be ignored.</li>
 * </ul>
 * 
 * @author JSON.org
 * @version 2
 */
public class JSONObject {

	/**
	 * JSONObject.NULL is equivalent to the value that JavaScript calls null, whilst Java's null is equivalent to the value that JavaScript calls undefined.
	 */

	private static final class Null {

		/**
		 * There is only intended to be a single instance of the NULL object, so the clone method returns itself.
		 * 
		 * @return NULL.
		 */
		protected final Object clone() {
			return this;
		}

		/**
		 * A Null object is equal to the null value and to itself.
		 * 
		 * @param object
		 *            An object to test for nullness.
		 * @return true if the object parameter is the JSONObject.NULL object or null.
		 */
		public boolean equals(Object object) {
			return (object == null) || (object == this);
		}

		/**
		 * Get the "null" string value.
		 * 
		 * @return The string "null".
		 */
		public String toString() {
			return "null";
		}
	}

	/**
	 * The hash map where the JSONObject's properties are kept.
	 */
	private Hashtable myHashMap;

	/**
	 * It is sometimes more convenient and less ambiguous to have a <code>NULL</code> object than to use Java's <code>null</code> value. <code>JSONObject.NULL.equals(null)</code> returns <code>true</code>. <code>JSONObject.NULL.toString()</code> returns <code>"null"</code>.
	 */
	public static final Object NULL = new Null();

	/**
	 * Construct an empty JSONObject.
	 */
	public JSONObject() {
		myHashMap = new Hashtable();
	}

	/**
	 * Construct a JSONObject from a subset of another JSONObject. An array of strings is used to identify the keys that should be copied. Missing keys are ignored.
	 * 
	 * @param jo
	 *            A JSONObject.
	 * @param sa
	 *            An array of strings.
	 * @exception JSONException
	 *                If a value is a non-finite number.
	 */
	public JSONObject(JSONObject jo, String[] sa) throws JSONException {
		this();
		for (int i = 0; i < sa.length; i += 1) {
			putOpt(sa[i], jo.opt(sa[i]));
		}
	}

	/**
	 * Construct a JSONObject from a JSONTokener.
	 * 
	 * @param x
	 *            A JSONTokener object containing the source string.
	 * @throws JSONException
	 *             If there is a syntax error in the source string.
	 */
	public JSONObject(JSONTokener x) throws JSONException {
		this();
		char c;
		String key;

		if (x.nextClean() != '{') {
			throw x.syntaxError("A JSONObject text must begin with '{'");
		}
		for (;;) {
			c = x.nextClean();
			switch (c) {
			case 0:
				throw x.syntaxError("A JSONObject text must end with '}'");
			case '}':
				return;
			default:
				x.back();
				key = x.nextValue().toString();
			}

			/*
			 * The key is followed by ':'. We will also tolerate '=' or '=>'.
			 */

			c = x.nextClean();
			if (c == '=') {
				if (x.next() != '>') {
					x.back();
				}
			} else if (c != ':') {
				throw x.syntaxError("Expected a ':' after a key");
			}
			put(key, x.nextValue());

			/*
			 * Pairs are separated by ','. We will also tolerate ';'.
			 */

			switch (x.nextClean()) {
			case ';':
			case ',':
				if (x.nextClean() == '}') {
					return;
				}
				x.back();
				break;
			case '}':
				return;
			default:
				throw x.syntaxError("Expected a ',' or '}'");
			}
		}
	}

	/**
	 * Construct a JSONObject from a Map.
	 * 
	 * @param map
	 *            A map object that can be used to initialize the contents of the JSONObject.
	 */
	public JSONObject(Hashtable map) {
		if (map == null) {
			myHashMap = new Hashtable();
		} else {
			myHashMap = new Hashtable(map.size());
			Enumeration keys = map.keys();
			while (keys.hasMoreElements()) {
				Object key = keys.nextElement();
				myHashMap.put(key, map.get(key));
			}
		}
	}

	/**
	 * Construct a JSONObject from a string. This is the most commonly used JSONObject constructor.
	 * 
	 * @param string
	 *            A string beginning with <code>{</code>&nbsp;<small>(left brace)</small> and ending with <code>}</code>&nbsp;<small>(right brace)</small>.
	 * @exception JSONException
	 *                If there is a syntax error in the source string.
	 */
	public JSONObject(String string) throws JSONException {
		this(new JSONTokener(string));
	}

	/**
	 * Accumulate values under a key. It is similar to the put method except that if there is already an object stored under the key then a JSONArray is stored under the key to hold all of the accumulated values. If there is already a JSONArray, then the new value is appended to it. In contrast, the put method replaces the previous value.
	 * 
	 * @param key
	 *            A key string.
	 * @param value
	 *            An object to be accumulated under the key.
	 * @return this.
	 * @throws JSONException
	 *             If the value is an invalid number or if the key is null.
	 */
	public JSONObject accumulate(String key, Object value) throws JSONException {
		testValidity(value);
		Object o = opt(key);
		if (o == null) {
			put(key, value);
		} else if (o instanceof JSONArray) {
			((JSONArray) o).put(value);
		} else {
			put(key, new JSONArray().put(o).put(value));
		}
		return this;
	}

	/**
	 * Append values to the array under a key. If the key does not exist in the JSONObject, then the key is put in the JSONObject with its value being a JSONArray containing the value parameter. If the key was already associated with a JSONArray, then the value parameter is appended to it.
	 * 
	 * @param key
	 *            A key string.
	 * @param value
	 *            An object to be accumulated under the key.
	 * @return this.
	 * @throws JSONException
	 *             If the key is null or if the current value associated with the key is not a JSONArray.
	 */
	public JSONObject append(String key, Object value) throws JSONException {
		testValidity(value);
		Object o = opt(key);
		if (o == null) {
			put(key, new JSONArray().put(value));
		} else if (o instanceof JSONArray) {
			throw new JSONException("JSONObject[" + key + "] is not a JSONArray.");
		} else {
			put(key, new JSONArray().put(o).put(value));
		}
		return this;
	}

	/**
	 * Produce a string from a double. The string "null" will be returned if the number is not finite.
	 * 
	 * @param d
	 *            A double.
	 * @return A String.
	 */
	static public String doubleToString(double d) {
		if (Double.isInfinite(d) || Double.isNaN(d)) {
			return "null";
		}

		// Shave off trailing zeros and decimal point, if possible.

		String s = Double.toString(d);
		if ((s.indexOf('.') > 0) && (s.indexOf('e') < 0) && (s.indexOf('E') < 0)) {
			while (s.endsWith("0")) {
				s = s.substring(0, s.length() - 1);
			}
			if (s.endsWith(".")) {
				s = s.substring(0, s.length() - 1);
			}
		}
		return s;
	}

	/**
	 * Get the value object associated with a key.
	 * 
	 * @param key
	 *            A key string.
	 * @return The object associated with the key.
	 * @throws JSONException
	 *             if the key is not found.
	 */
	public Object get(String key) throws JSONException {
		Object o = opt(key);
		if (o == null) {
			throw new JSONException("JSONObject[" + quote(key) + "] not found.");
		}
		return o;
	}

	/**
	 * Get the boolean value associated with a key.
	 * 
	 * @param key
	 *            A key string.
	 * @return The truth.
	 * @throws JSONException
	 *             if the value is not a Boolean or the String "true" or "false".
	 */
	public boolean getBoolean(String key) throws JSONException {
		Object o = get(key);
		if (o.equals(Boolean.FALSE) || ((o instanceof String) && ((String) o).equalsIgnoreCase("false"))) {
			return false;
		} else if (o.equals(Boolean.TRUE) || ((o instanceof String) && ((String) o).equalsIgnoreCase("true"))) {
			return true;
		}
		throw new JSONException("JSONObject[" + quote(key) + "] is not a Boolean.");
	}

	/**
	 * Get the double value associated with a key.
	 * 
	 * @param key
	 *            A key string.
	 * @return The numeric value.
	 * @throws JSONException
	 *             if the key is not found or if the value is not a Number object and cannot be converted to a number.
	 */
	public double getDouble(String key) throws JSONException {
		Object o = get(key);
		if (o instanceof Byte) {
			return ((Byte) o).byteValue();
		} else if (o instanceof Short) {
			return ((Short) o).shortValue();
		} else if (o instanceof Integer) {
			return ((Integer) o).intValue();
		} else if (o instanceof Long) {
			return ((Long) o).longValue();
		} else if (o instanceof Float) {
			return ((Float) o).floatValue();
		} else if (o instanceof Double) {
			return ((Double) o).doubleValue();
		} else if (o instanceof String) {
			try {
				return Double.valueOf((String) o).doubleValue();
			} catch (Exception e) {
				throw new JSONException("JSONObject[" + quote(key) + "] is not a number.");
			}
		}
		throw new JSONException("JSONObject[" + quote(key) + "] is not a number.");
	}

	/**
	 * Get the int value associated with a key. If the number value is too large for an int, it will be clipped.
	 * 
	 * @param key
	 *            A key string.
	 * @return The integer value.
	 * @throws JSONException
	 *             if the key is not found or if the value cannot be converted to an integer.
	 */
	public int getInt(String key) throws JSONException {
		Object o = get(key);
		if (o instanceof Byte) {
			return ((Byte) o).byteValue();
		} else if (o instanceof Short) {
			return ((Short) o).shortValue();
		} else if (o instanceof Integer) {
			return ((Integer) o).intValue();
		} else if (o instanceof Long) {
			return (int) ((Long) o).longValue();
		} else if (o instanceof Float) {
			return (int) ((Float) o).floatValue();
		} else if (o instanceof Double) {
			return (int) ((Double) o).doubleValue();
		} else if (o instanceof String) {
			return (int) getDouble(key);
		}
		throw new JSONException("JSONObject[" + quote(key) + "] is not a number.");
	}

	/**
	 * Get the JSONArray value associated with a key.
	 * 
	 * @param key
	 *            A key string.
	 * @return A JSONArray which is the value.
	 * @throws JSONException
	 *             if the key is not found or if the value is not a JSONArray.
	 */
	public JSONArray getJSONArray(String key) throws JSONException {
		Object o = get(key);
		if (o instanceof JSONArray) {
			return (JSONArray) o;
		}
		throw new JSONException("JSONObject[" + quote(key) + "] is not a JSONArray.");
	}

	/**
	 * Get the JSONObject value associated with a key.
	 * 
	 * @param key
	 *            A key string.
	 * @return A JSONObject which is the value.
	 * @throws JSONException
	 *             if the key is not found or if the value is not a JSONObject.
	 */
	public JSONObject getJSONObject(String key) throws JSONException {
		Object o = get(key);
		if (o instanceof JSONObject) {
			return (JSONObject) o;
		}
		throw new JSONException("JSONObject[" + quote(key) + "] is not a JSONObject.");
	}

	/**
	 * Get the long value associated with a key. If the number value is too long for a long, it will be clipped.
	 * 
	 * @param key
	 *            A key string.
	 * @return The long value.
	 * @throws JSONException
	 *             if the key is not found or if the value cannot be converted to a long.
	 */
	public long getLong(String key) throws JSONException {
		Object o = get(key);
		if (o instanceof Byte) {
			return ((Byte) o).byteValue();
		} else if (o instanceof Short) {
			return ((Short) o).shortValue();
		} else if (o instanceof Integer) {
			return ((Integer) o).intValue();
		} else if (o instanceof Long) {
			return ((Long) o).longValue();
		} else if (o instanceof Float) {
			return (long) ((Float) o).floatValue();
		} else if (o instanceof Double) {
			return (long) ((Double) o).doubleValue();
		} else if (o instanceof String) {
			return (long) getDouble(key);
		}
		throw new JSONException("JSONObject[" + quote(key) + "] is not a number.");
	}

	/**
	 * Get the string associated with a key.
	 * 
	 * @param key
	 *            A key string.
	 * @return A string which is the value.
	 * @throws JSONException
	 *             if the key is not found.
	 */
	public String getString(String key) throws JSONException {
		return get(key).toString();
	}

	/**
	 * Determine if the JSONObject contains a specific key.
	 * 
	 * @param key
	 *            A key string.
	 * @return true if the key exists in the JSONObject.
	 */
	public boolean has(String key) {
		return myHashMap.containsKey(key);
	}

	/**
	 * Determine if the value associated with the key is null or if there is no value.
	 * 
	 * @param key
	 *            A key string.
	 * @return true if there is no value associated with the key or if the value is the JSONObject.NULL object.
	 */
	public boolean isNull(String key) {
		return JSONObject.NULL.equals(opt(key));
	}

	/**
	 * Get an enumeration of the keys of the JSONObject.
	 * 
	 * @return An iterator of the keys.
	 */
	public Enumeration keys() {
		return myHashMap.keys();
	}

	/**
	 * Get the number of keys stored in the JSONObject.
	 * 
	 * @return The number of keys in the JSONObject.
	 */
	public int length() {
		return myHashMap.size();
	}

	/**
	 * Produce a JSONArray containing the names of the elements of this JSONObject.
	 * 
	 * @return A JSONArray containing the key strings, or null if the JSONObject is empty.
	 */
	public JSONArray names() {
		JSONArray ja = new JSONArray();
		Enumeration keys = keys();
		while (keys.hasMoreElements()) {
			ja.put(keys.nextElement());
		}
		return ja.length() == 0 ? null : ja;
	}

	/**
	 * Shave off trailing zeros and decimal point, if possible.
	 */
	static public String trimNumber(String s) {
		if ((s.indexOf('.') > 0) && (s.indexOf('e') < 0) && (s.indexOf('E') < 0)) {
			while (s.endsWith("0")) {
				s = s.substring(0, s.length() - 1);
			}
			if (s.endsWith(".")) {
				s = s.substring(0, s.length() - 1);
			}
		}
		return s;
	}

	/**
	 * Produce a string from a Number.
	 * 
	 * @param n
	 *            A Number
	 * @return A String.
	 * @throws JSONException
	 *             If n is a non-finite number.
	 */
	static public String numberToString(Object n) throws JSONException {
		if (n == null) {
			throw new JSONException("Null pointer");
		}
		testValidity(n);
		return trimNumber(n.toString());
	}

	/**
	 * Get an optional value associated with a key.
	 * 
	 * @param key
	 *            A key string.
	 * @return An object which is the value, or null if there is no value.
	 */
	public Object opt(String key) {
		return key == null ? null : myHashMap.get(key);
	}

	/**
	 * Get an optional boolean associated with a key. It returns false if there is no such key, or if the value is not Boolean.TRUE or the String "true".
	 * 
	 * @param key
	 *            A key string.
	 * @return The truth.
	 */
	public boolean optBoolean(String key) {
		return optBoolean(key, false);
	}

	/**
	 * Get an optional boolean associated with a key. It returns the defaultValue if there is no such key, or if it is not a Boolean or the String "true" or "false" (case insensitive).
	 * 
	 * @param key
	 *            A key string.
	 * @param defaultValue
	 *            The default.
	 * @return The truth.
	 */
	public boolean optBoolean(String key, boolean defaultValue) {
		try {
			return getBoolean(key);
		} catch (Exception e) {
			return defaultValue;
		}
	}

	/**
	 * Put a key/value pair in the JSONObject, where the value will be a JSONArray which is produced from a Collection.
	 * 
	 * @param key
	 *            A key string.
	 * @param value
	 *            A Collection value.
	 * @return this.
	 * @throws JSONException
	 */
	public JSONObject put(String key, Vector value) throws JSONException {
		put(key, new JSONArray(value));
		return this;
	}

	/**
	 * Get an optional double associated with a key, or NaN if there is no such key or if its value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
	 * 
	 * @param key
	 *            A string which is the key.
	 * @return An object which is the value.
	 */
	public double optDouble(String key) {
		return optDouble(key, Double.NaN);
	}

	/**
	 * Get an optional double associated with a key, or the defaultValue if there is no such key or if its value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
	 * 
	 * @param key
	 *            A key string.
	 * @param defaultValue
	 *            The default.
	 * @return An object which is the value.
	 */
	public double optDouble(String key, double defaultValue) {
		try {
			Object o = opt(key);
			return Double.parseDouble((String) o);
		} catch (Exception e) {
			return defaultValue;
		}
	}

	/**
	 * Get an optional int value associated with a key, or zero if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
	 * 
	 * @param key
	 *            A key string.
	 * @return An object which is the value.
	 */
	public int optInt(String key) {
		return optInt(key, 0);
	}

	/**
	 * Get an optional int value associated with a key, or the default if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
	 * 
	 * @param key
	 *            A key string.
	 * @param defaultValue
	 *            The default.
	 * @return An object which is the value.
	 */
	public int optInt(String key, int defaultValue) {
		try {
			return getInt(key);
		} catch (Exception e) {
			return defaultValue;
		}
	}

	/**
	 * Get an optional JSONArray associated with a key. It returns null if there is no such key, or if its value is not a JSONArray.
	 * 
	 * @param key
	 *            A key string.
	 * @return A JSONArray which is the value.
	 */
	public JSONArray optJSONArray(String key) {
		Object o = opt(key);
		return o instanceof JSONArray ? (JSONArray) o : null;
	}

	/**
	 * Get an optional JSONObject associated with a key. It returns null if there is no such key, or if its value is not a JSONObject.
	 * 
	 * @param key
	 *            A key string.
	 * @return A JSONObject which is the value.
	 */
	public JSONObject optJSONObject(String key) {
		Object o = opt(key);
		return o instanceof JSONObject ? (JSONObject) o : null;
	}

	/**
	 * Get an optional long value associated with a key, or zero if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
	 * 
	 * @param key
	 *            A key string.
	 * @return An object which is the value.
	 */
	public long optLong(String key) {
		return optLong(key, 0);
	}

	/**
	 * Get an optional long value associated with a key, or the default if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
	 * 
	 * @param key
	 *            A key string.
	 * @param defaultValue
	 *            The default.
	 * @return An object which is the value.
	 */
	public long optLong(String key, long defaultValue) {
		try {
			return getLong(key);
		} catch (Exception e) {
			return defaultValue;
		}
	}

	/**
	 * Get an optional string associated with a key. It returns an empty string if there is no such key. If the value is not a string and is not null, then it is coverted to a string.
	 * 
	 * @param key
	 *            A key string.
	 * @return A string which is the value.
	 */
	public String optString(String key) {
		return optString(key, "");
	}

	/**
	 * Get an optional string associated with a key. It returns the defaultValue if there is no such key.
	 * 
	 * @param key
	 *            A key string.
	 * @param defaultValue
	 *            The default.
	 * @return A string which is the value.
	 */
	public String optString(String key, String defaultValue) {
		Object o = opt(key);
		return o != null ? o.toString() : defaultValue;
	}

	/**
	 * Put a key/boolean pair in the JSONObject.
	 * 
	 * @param key
	 *            A key string.
	 * @param value
	 *            A boolean which is the value.
	 * @return this.
	 * @throws JSONException
	 *             If the key is null.
	 */
	public JSONObject put(String key, boolean value) throws JSONException {
		put(key, value ? Boolean.TRUE : Boolean.FALSE);
		return this;
	}

	/**
	 * Put a key/double pair in the JSONObject.
	 * 
	 * @param key
	 *            A key string.
	 * @param value
	 *            A double which is the value.
	 * @return this.
	 * @throws JSONException
	 *             If the key is null or if the number is invalid.
	 */
	public JSONObject put(String key, double value) throws JSONException {
		put(key, new Double(value));
		return this;
	}

	/**
	 * Put a key/int pair in the JSONObject.
	 * 
	 * @param key
	 *            A key string.
	 * @param value
	 *            An int which is the value.
	 * @return this.
	 * @throws JSONException
	 *             If the key is null.
	 */
	public JSONObject put(String key, int value) throws JSONException {
		put(key, new Integer(value));
		return this;
	}

	/**
	 * Put a key/long pair in the JSONObject.
	 * 
	 * @param key
	 *            A key string.
	 * @param value
	 *            A long which is the value.
	 * @return this.
	 * @throws JSONException
	 *             If the key is null.
	 */
	public JSONObject put(String key, long value) throws JSONException {
		put(key, new Long(value));
		return this;
	}

	/**
	 * Put a key/value pair in the JSONObject, where the value will be a JSONObject which is produced from a Map.
	 * 
	 * @param key
	 *            A key string.
	 * @param value
	 *            A Map value.
	 * @return this.
	 * @throws JSONException
	 */
	public JSONObject put(String key, Hashtable value) throws JSONException {
		put(key, new JSONObject(value));
		return this;
	}

	/**
	 * Put a key/value pair in the JSONObject. If the value is null, then the key will be removed from the JSONObject if it is present.
	 * 
	 * @param key
	 *            A key string.
	 * @param value
	 *            An object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object.
	 * @return this.
	 * @throws JSONException
	 *             If the value is non-finite number or if the key is null.
	 */
	public JSONObject put(String key, Object value) throws JSONException {
		if (key == null) {
			throw new JSONException("Null key.");
		}
		if (value != null) {
			testValidity(value);
			myHashMap.put(key, value);
		} else {
			remove(key);
		}
		return this;
	}

	/**
	 * Put a key/value pair in the JSONObject, but only if the key and the value are both non-null.
	 * 
	 * @param key
	 *            A key string.
	 * @param value
	 *            An object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object.
	 * @return this.
	 * @throws JSONException
	 *             If the value is a non-finite number.
	 */
	public JSONObject putOpt(String key, Object value) throws JSONException {
		if ((key != null) && (value != null)) {
			put(key, value);
		}
		return this;
	}

	/**
	 * Produce a string in double quotes with backslash sequences in all the right places. A backslash will be inserted within </, allowing JSON text to be delivered in HTML. In JSON text, a string cannot contain a control character or an unescaped quote or backslash.
	 * 
	 * @param string
	 *            A String
	 * @return A String correctly formatted for insertion in a JSON text.
	 */
	public static String quote(String string) {
		if ((string == null) || (string.length() == 0)) {
			return "\"\"";
		}

		char b;
		char c = 0;
		int i;
		int len = string.length();
		StringBuffer sb = new StringBuffer(len + 4);
		String t;

		sb.append('"');
		for (i = 0; i < len; i += 1) {
			b = c;
			c = string.charAt(i);
			switch (c) {
			case '\\':
			case '"':
				sb.append('\\');
				sb.append(c);
				break;
			case '/':
				if (b == '<') {
					sb.append('\\');
				}
				sb.append(c);
				break;
			case '\b':
				sb.append("\\b");
				break;
			case '\t':
				sb.append("\\t");
				break;
			case '\n':
				sb.append("\\n");
				break;
			case '\f':
				sb.append("\\f");
				break;
			case '\r':
				sb.append("\\r");
				break;
			default:
				if (c < ' ') {
					t = "000" + Integer.toHexString(c);
					sb.append("\\u" + t.substring(t.length() - 4));
				} else {
					sb.append(c);
				}
			}
		}
		sb.append('"');
		return sb.toString();
	}

	/**
	 * Remove a name and its value, if present.
	 * 
	 * @param key
	 *            The name to be removed.
	 * @return The value that was associated with the name, or null if there was no value.
	 */
	public Object remove(String key) {
		return myHashMap.remove(key);
	}

	/**
	 * Throw an exception if the object is an NaN or infinite number.
	 * 
	 * @param o
	 *            The object to test.
	 * @throws JSONException
	 *             If o is a non-finite number.
	 */
	static void testValidity(Object o) throws JSONException {
		if (o != null) {
			if (o instanceof Double) {
				if (((Double) o).isInfinite() || ((Double) o).isNaN()) {
					throw new JSONException("JSON does not allow non-finite numbers");
				}
			} else if (o instanceof Float) {
				if (((Float) o).isInfinite() || ((Float) o).isNaN()) {
					throw new JSONException("JSON does not allow non-finite numbers.");
				}
			}
		}
	}

	/**
	 * Produce a JSONArray containing the values of the members of this JSONObject.
	 * 
	 * @param names
	 *            A JSONArray containing a list of key strings. This determines the sequence of the values in the result.
	 * @return A JSONArray of values.
	 * @throws JSONException
	 *             If any of the values are non-finite numbers.
	 */
	public JSONArray toJSONArray(JSONArray names) throws JSONException {
		if ((names == null) || (names.length() == 0)) {
			return null;
		}
		JSONArray ja = new JSONArray();
		for (int i = 0; i < names.length(); i += 1) {
			ja.put(opt(names.getString(i)));
		}
		return ja;
	}

	/**
	 * Make a JSON text of this JSONObject. For compactness, no whitespace is added. If this would not result in a syntactically correct JSON text, then null will be returned instead.
	 * <p>
	 * Warning: This method assumes that the data structure is acyclical.
	 * 
	 * @return a printable, displayable, portable, transmittable representation of the object, beginning with <code>{</code>&nbsp;<small>(left brace)</small> and ending with <code>}</code>&nbsp;<small>(right brace)</small>.
	 */
	public String toString() {
		try {
			Enumeration keys = keys();
			StringBuffer sb = new StringBuffer("{");

			while (keys.hasMoreElements()) {
				if (sb.length() > 1) {
					sb.append(',');
				}
				Object o = keys.nextElement();
				sb.append(quote(o.toString()));
				sb.append(':');
				sb.append(valueToString(myHashMap.get(o)));
			}
			sb.append('}');
			return sb.toString();
		} catch (Exception e) {
			return null;
		}
	}

	/**
	 * Make a prettyprinted JSON text of this JSONObject.
	 * <p>
	 * Warning: This method assumes that the data structure is acyclical.
	 * 
	 * @param indentFactor
	 *            The number of spaces to add to each level of indentation.
	 * @return a printable, displayable, portable, transmittable representation of the object, beginning with <code>{</code>&nbsp;<small>(left brace)</small> and ending with <code>}</code>&nbsp;<small>(right brace)</small>.
	 * @throws JSONException
	 *             If the object contains an invalid number.
	 */
	public String toString(int indentFactor) throws JSONException {
		return toString(indentFactor, 0);
	}

	/**
	 * Make a prettyprinted JSON text of this JSONObject.
	 * <p>
	 * Warning: This method assumes that the data structure is acyclical.
	 * 
	 * @param indentFactor
	 *            The number of spaces to add to each level of indentation.
	 * @param indent
	 *            The indentation of the top level.
	 * @return a printable, displayable, transmittable representation of the object, beginning with <code>{</code>&nbsp;<small>(left brace)</small> and ending with <code>}</code>&nbsp;<small>(right brace)</small>.
	 * @throws JSONException
	 *             If the object contains an invalid number.
	 */
	String toString(int indentFactor, int indent) throws JSONException {
		int i;
		int n = length();
		if (n == 0) {
			return "{}";
		}
		Enumeration keys = keys();
		StringBuffer sb = new StringBuffer("{");
		int newindent = indent + indentFactor;
		Object o;
		if (n == 1) {
			o = keys.nextElement();
			sb.append(quote(o.toString()));
			sb.append(": ");
			sb.append(valueToString(myHashMap.get(o), indentFactor, indent));
		} else {
			while (keys.hasMoreElements()) {
				o = keys.nextElement();
				if (sb.length() > 1) {
					sb.append(",\n");
				} else {
					sb.append('\n');
				}
				for (i = 0; i < newindent; i += 1) {
					sb.append(' ');
				}
				sb.append(quote(o.toString()));
				sb.append(": ");
				sb.append(valueToString(myHashMap.get(o), indentFactor, newindent));
			}
			if (sb.length() > 1) {
				sb.append('\n');
				for (i = 0; i < indent; i += 1) {
					sb.append(' ');
				}
			}
		}
		sb.append('}');
		return sb.toString();
	}

	/**
	 * Make a JSON text of an FacebookObject value. If the object has an value.toJSONString() method, then that method will be used to produce the JSON text. The method is required to produce a strictly conforming text. If the object does not contain a toJSONString method (which is the most common case), then a text will be produced by the rules.
	 * <p>
	 * Warning: This method assumes that the data structure is acyclical.
	 * 
	 * @param value
	 *            The value to be serialized.
	 * @return a printable, displayable, transmittable representation of the object, beginning with <code>{</code>&nbsp;<small>(left brace)</small> and ending with <code>}</code>&nbsp;<small>(right brace)</small>.
	 * @throws JSONException
	 *             If the value is or contains an invalid number.
	 */
	static String valueToString(Object value) throws JSONException {
		if ((value == null) || value.equals(null)) {
			return "null";
		}
		if (value instanceof JSONString) {
			Object o;
			try {
				o = ((JSONString) value).toJSONString();
			} catch (Exception e) {
				throw new JSONException(e);
			}
			if (o instanceof String) {
				return (String) o;
			}
			throw new JSONException("Bad value from toJSONString: " + o);
		}
		if ((value instanceof Float) || (value instanceof Double) || (value instanceof Byte) || (value instanceof Short) || (value instanceof Integer) || (value instanceof Long)) {
			return numberToString(value);
		}
		if ((value instanceof Boolean) || (value instanceof JSONObject) || (value instanceof JSONArray)) {
			return value.toString();
		}
		return quote(value.toString());
	}

	/**
	 * Make a prettyprinted JSON text of an object value.
	 * <p>
	 * Warning: This method assumes that the data structure is acyclical.
	 * 
	 * @param value
	 *            The value to be serialized.
	 * @param indentFactor
	 *            The number of spaces to add to each level of indentation.
	 * @param indent
	 *            The indentation of the top level.
	 * @return a printable, displayable, transmittable representation of the object, beginning with <code>{</code>&nbsp;<small>(left brace)</small> and ending with <code>}</code>&nbsp;<small>(right brace)</small>.
	 * @throws JSONException
	 *             If the object contains an invalid number.
	 */
	static String valueToString(Object value, int indentFactor, int indent) throws JSONException {
		if ((value == null) || value.equals(null)) {
			return "null";
		}
		try {
			if (value instanceof JSONString) {
				Object o = ((JSONString) value).toJSONString();
				if (o instanceof String) {
					return (String) o;
				}
			}
		} catch (Exception e) {
			/* forget about it */
		}
		if ((value instanceof Float) || (value instanceof Double) || (value instanceof Byte) || (value instanceof Short) || (value instanceof Integer) || (value instanceof Long)) {
			return numberToString(value);
		}
		if (value instanceof Boolean) {
			return value.toString();
		}
		if (value instanceof JSONObject) {
			return ((JSONObject) value).toString(indentFactor, indent);
		}
		if (value instanceof JSONArray) {
			return ((JSONArray) value).toString(indentFactor, indent);
		}
		return quote(value.toString());
	}

	/**
	 * Write the contents of the JSONObject as JSON text to a writer. For compactness, no whitespace is added.
	 * <p>
	 * Warning: This method assumes that the data structure is acyclical.
	 * 
	 * @return The writer.
	 * @throws JSONException
	 */
	public Writer write(Writer writer) throws JSONException {
		try {
			boolean b = false;
			Enumeration keys = keys();
			writer.write('{');

			while (keys.hasMoreElements()) {
				if (b) {
					writer.write(',');
				}
				Object k = keys.nextElement();
				writer.write(quote(k.toString()));
				writer.write(':');
				Object v = myHashMap.get(k);
				if (v instanceof JSONObject) {
					((JSONObject) v).write(writer);
				} else if (v instanceof JSONArray) {
					((JSONArray) v).write(writer);
				} else {
					writer.write(valueToString(v));
				}
				b = true;
			}
			writer.write('}');
			return writer;
		} catch (IOException e) {
			throw new JSONException(e);
		}
	}
}